Summary C-GRNE, a Piper PA-31 Navajo, was on arrival to Winnipeg International Airport (the airport), on radar vectors for a left-hand approach to runway 36. The arrival controller had cleared the aircraft to descend to 3000 feet. C-GKGY, a Mooney M20C departing on an instrument flight rules flight plan off runway 36, was given a left-turn heading of 270 degrees and cleared to climb to 6000 feet by the departure controller. As they passed 5 nautical miles (nm) west of the airport, the separation between the two aircraft was 0.53 nm lateral and 300 feet vertical. The required separation in this area was 3 nm lateral or 1000 feet vertical. Ce rapport est galement disponible en franais. Other Factual Information The Piper Navajo, C-GRNE, on an instrument flight rules (IFR) flight to Winnipeg, was being vectored to the airport by the arrival controller for a visual approach to runway 36. The aircraft was maintaining 7000 feet when the arrival controller accepted control of the aircraft.(1) At 1211:28 central daylight time the pilot of the Navajo requested descent clearance (see Appendix A - Sequence of Events).(2) Since the aircraft was flying in the departure controller's airspace, coordination was required with the departure controller for a lower altitude. The arrival controller noted that the departure controller was busy, and so did not initiate coordination at that time. At 1212:08, after receiving approval from the data controller, located between the departure and arrival controllers, the arrival controller cleared the Navajo to descend to 5000 feet. Normally, approval for descent was verbally coordinated directly between the arrival and departure controllers. Then, at approximately 1216, the departure controller advised the arrival controller that descent to 3000 feet without restrictions was approved for the Navajo. The aircraft was 11 nm northwest of the airport at the time, still within the departure controller's airspace. At 1214:18, the tower requested and received approval from the departure controller to turn C-GKGY, a Mooney M20C about to take off from runway 36 on an IFR flight, early rather than climb runway heading, in an effort to expedite the departure flow. The tower and departure controllers coordinated an initial departure heading of 250 degrees. The Mooney took off at 1216:24 and turned left at about mid-field to 250 degrees. On initial contact with the departure controller, the Mooney was identified and issued a right turn to a heading of 270 degrees and was to continue the climb to 6000 feet. Neither the arrival controller nor the departure controller was aware that the two aircraft were approaching each other at the same altitude with less than the required radar separation (see Figure 1). It was the data controller who alerted the arrival controller to the impending conflict. The arrival controller immediately instructed the Navajo to descend to 2500 feet and, six seconds later, at 1219:33, issued traffic information on the Mooney. At 1219:34 the departure controller issued traffic information on the Navajo to the Mooney. Nine seconds later, the pilot of the Mooney advised the traffic in sight. Analysis of the recorded radar data indicated that the Navajo crossed 0.53 nm directly in front of and 300 feet below the Mooney in an area where 3 nm lateral or 1000 feet vertical spacing is the minimum required separation in accordance with Canadian Aviation Regulation 801.08. There is no functioning conflict-alerting tool available to warn controllers of an impending conflict. Except for the Navajo and the Mooney, there was no other traffic of concern to the west of the airport for the arrival or the departure controller. The departure controller was controlling four aircraft, primarily to the north and east of Winnipeg. The arrival controller was controlling four aircraft to the east and southeast. The arrival controller was concerned with three visual flight rules (VFR) aircraft that had departed eastbound and were traffic for one of the arrivals. For 1 minute 12 seconds before the loss of separation, the arrival controller was busy trying to sort out a request from another arriving aircraft for a type of approach unfamiliar to the arrival controller. The arrival controller's attention was diverted from his other controlling tasks until the data controller called his attention to the conflict between the Navajo and the Mooney. Figure 1 - Navajo and Mooney - 1 nm apart at the same altitude, at 1219:35 Many of the aircraft flying into and out of Winnipeg airport on a daily basis have become familiar with the procedures used by controllers for assigning altitudes to arriving aircraft. Pilots have come to expect descent clearance as early as possible, especially if visual approaches are in effect. In an effort to provide a safe and efficient service, arrival controllers routinely coordinate lower altitudes with the departure controller prior to arriving aircraft reaching the dump zone--airspace under the jurisdiction of the arrival controller. In this occurrence, the Navajo was authorized to descend (after coordination) to 5000 feet , then to 3000 feet, while the aircraft was still north of the dump zone. When the departure controller authorized descent for the Navajo to 3000 feet, he did not advise the arrival controller that there would be traffic departing westbound, climbing to 6000 feet. It was normal practice for the departure controller when approving descent to also coordinate any traffic of concern to the arrival controller, along with any avoidance required. There were six controllers, including the supervisor, on duty in the Winnipeg Terminal Specialty at the time of the occurrence. Four control positions were active: arrival, departure, data, and VFR traffic advisory. Traffic in the arrival position was reported to be light to moderate with normal complexity. The departure controller was experiencing moderate traffic levels with moderate complexity. The staffing level was in accordance with unit policy and was compatible with the traffic levels. Arriving and departing traffic is routed into and out of Winnipeg Terminal Control Unit (TCU) airspace via specific entry and exit gates. Arrival and departure controllers therefore are required to coordinate the climb and descent of aircraft on crossing tracks in accordance with standard procedures contained in Operations Letter OL-97-006--Procedures Pertaining to the Terminal Specialty, dated 15 May 1997. This letter specifies the division and coordination of airspace between arrival and departure control. An (approximately) east-west line, based on the 090- and 265-degree radials of the Winnipeg VORTAC (combined very high frequency omnidirectional radio range and tactical air navigation aid), delineates the airspace controlled by the arrival and departure controllers. According to Operations Letter OL-97-006, when runways 31, 36 and/or 07 are active, descent to 5000 feet for aircraft arriving from the west requires prior coordination with the departure controller. However, once an aircraft has crossed the 090- or 265-degree radial southbound, the arrival controller is no longer required to coordinate with the departure controller to descend arriving traffic. Runway 36 was the active runway, and runway 31 was available for use after coordination between the tower and terminal. Departures were issued published standard instrument departure (SID) procedures in accordance with Operations Letter OL-97-006. The SID for runway 36 requires the aircraft to climb to 4000 feet (or flight-planned altitude, if lower), and to expect radar vectors. A review of communications between the departure controller and departing aircraft in the 10-minute period preceding the occurrence revealed that, on initial contact, the majority of aircraft were being instructed to continue on runway heading. The Mooney, on the other hand, had been instructed to commence an immediate turn to the west after departure, a manoeuvre normally associated with VFR departures. The data controller is, in part, responsible for receiving and passing estimates, annotating and writing flight progress strips, answering the telephones, and acting as a second pair of eyes and ears for the arrival controller. The data controller may also initiate coordination to assist the arrival and departure controllers. The data controller's position is physically located between the arrival and departure positions. According to information received during the investigation, the data controller is responsive to, and works most closely with, the arrival controller. Section 507 of the Air Traffic Control Manual of Operations (ATC MANOPS) provides phraseology that controllers are to use when issuing safety advisories to aircraft. Neither the arrival nor the departure controller used this phraseology when passing traffic information to the pilots of the Mooney and Navajo aircraft. Previous investigations conducted by the TSB have shown that when non-standard phraseology was used to alert aircrews to impending conflicts, there were delays in response from the aircrew because the sense of urgency to react was not always evident to them. The Air Traffic Services Administration and Management Manual (ATSAMM) states: managers shall ensure that operating procedures are in place that will allow the air traffic services unit to function with the highest degree of efficiency. Standard operating procedures provide a built-in level of safety and reduce the workload for the controller. The Human Factors section of NAV CANADA's Situational Awareness Training module for Air Traffic Services (ATS) personnel notes: Regulations and standard operating procedures (SOP) are usually the consequence of past actions. They are pre-made decisions with known outcomes. If we (controllers) depart from regulations or SOPs, we are operating in a gray area, where the outcomes of our actions cannot be predicted with any degree of certainty. Operations Letter OL-97-006 does not specifically state which controller, arrival or departure, is responsible to maintain his or her aircraft's separation from other traffic. It is generally understood, however, that the departure controller is responsible to keep departing traffic away from arrival traffic if descent is authorized within the departure airspace. The arrival controller had seen the radar target for the westbound departure when it initially appeared on the radar display but determined, based on its observed flight path (immediate turn after departure rather than runway heading), that it was probably a VFR flight. The arrival controller would have expected the departure controller to point out any IFR traffic of concern at the time authorization to descend the Navajo was issued to the arrival controller. When the VFR radar-monitoring position is active, as it was in this instance, the controller jurisdiction symbol (CJS) associated with that position is displayed beside the radar target and is an indication that the aircraft is a VFR flight. VFR flights are normally restricted to 2500 feet above sea level (asl) or less within 7 nm of the airport. However, if the VFR radar position is combined with the departure position, there is no way to distinguish a VFR radar target from an IFR radar target, because all targets controlled by the departure controller would display the departure CJS. Procedures have been developed at some NAV CANADA ATS units in which a supplementary character termed a special function indicator (SFI) is added to the aircraft identification display. Local procedures can define the SFI to mean, among other things, that a particular aircraft is a VFR flight. Such a procedure can make it easier for controllers to distinguish between IFR and VFR aircraft and has the potential to reduce the need for verbal coordination between arrival, departure, and tower controllers.